I'm thinking even a Honda MB5 has to work/be modded to go past 55 mph. It has a cluth and 5 gears.
If my goal is over 55 I'd start at a 125 Honda and preferably a 250.
Now I'm just as guilty, wanting more. By all means get all you mentioned + PW50 gears, have fun with assembly, get the best you can, but it won't be over 55 mph.
It will still be a blast!